The invention relates generally to a process for manufacturing an integrated circuit device. More specifically, the invention relates to processes for manufacturing integrated circuit devices using porous organosilicate systems templated with fugitive polymeric unimolecular micelles.
There is a continuing desire in the microelectronics industry to increase the circuit density in multilevel integrated circuit devices e.g., memory and logic chips, thereby increasing their performance and reducing their cost. In order to accomplish this goal, there is a desire to reduce the minimum feature size on the chip e.g., circuit linewidth, and also to decrease the dielectric constant of the interposed dielectric material to enable closer spacing of circuit lines without an increase in crosstalk and capacitive coupling. Further, there is a desire to reduce the dielectric constant of dielectric materials such as those utilized in the back end of the line (BEOL) portion of integrated circuit devices, which contain input/output circuitry, to reduce the requisite drive current and power consumption for the device. The present dielectric is silicon dioxide which has a dielectric constant of about 4.0.
This material has the requisite mechanical and thermal properties to withstand processing operations and thermal cycling associated with semiconductor manufacturing. However, it is desired that dielectric materials for future integrated circuit devices exhibit a lower dielectric constant (e.g.,  less than 3.0) than exhibited by current silicon dioxide.
It is therefore an object of the present invention to provide an improved integrated circuit device comprising an improved dielectric material.
Other objects and advantages of the invention will be apparent from the following disclosure.
The invention relates to a process for forming an integrated circuit device comprising (i) a substrate; (ii) interconnecting metallic circuit lines positioned on the substrate and (iii) a dielectric material positioned contiguous to the circuit lines (over and/or between the circuit lines). The dielectric material comprises a porous organic polysilica formed by the process of the invention. Preferably, the dielectric material has pore sizes of less than about 500 xc3x85.
A general route to organic-inorganic hybrids with nanophase morphologies has been developed with the objective of ultimately templating nanoporosity in organosilicates. Our invention concerns the preparation of macromolecular micelles which organize in the organosilicate. However, the self-organization of amphiphilic macromolecular species is a dynamic process and difficult to control and achieve, particularly in a ternary mixture (i.e., polymer, organosilicate and solvent).
One key feature of our invention is the use of macromolecules with star, hyper-star and dendrimer-like star molecular architectures. If properly designed, the interior of the star would be hydrophobic and the exterior hydrophilic, and such macromolecules are, themselves, micelles (e.g. unimolecular micelles). As a consequence, the dynamics of the micelle formation process are eliminated using these unimolecular micelles. The processes involved in forming nanostructures in hybrids with organosilicates are also greatly simplified. The synthesis of the unimolecular micelles has been demonstrated by the preparation of poly(caprolactone)/poly(methyl methacrylate-co-hydroxyethyl methacrylate) copolymers with various levels of hydroxyethyl methacrylate to control the hydrophilicity. These copolymers are sufficiently thermally stable to allow vitrification of the organosilicate component in the hybrids, yet decompose quantitatively at elevated temperatures to leave behind the templated nonoporosity.
The invention uses covalently bound 3-dimensional molecules, or macromolecular assemblies, to create nanoporosity in thermosetting matrixes. The matrixes can be inorganic thermosets, silsesquioxanes, or organic silicas, or organic thermosetting resins such as SiLK which is available from Dow Chemical Company or others. In addition, all the pore generating materials have a 3-dimensional structure which results in a low level of self-interaction. This low level of self-interaction leads to a more homogeneous distribution of pore generating materials throughout the matrix with the ultimate objective being complete miscibility and nanometer-sized domains.
For most linear polymers, or typical polymer micelles, aggregation occurs during processing which leads to micron sized domains which are not compatible with our desired microelectronic applications. Another advantage of these 3-dimensional pore generators is that the functionality on the periphery, or surface layer, as well as in the interior can be accurately controlled and varied. This permits the interaction of these materials with the chosen matrix to be fine tuned in order to maximize miscibility and nanoscopic structure.
A more thorough disclosure of the invention is presented in the detailed description which follows and from the accompanying drawings.